Ignacio.

I worked as a Tech Lead Software Engineer at Bether, where I was responsible for leading the development of a new web application. Starting from a demo frontend prototype, I have been involved in the design and implementation of the backend architecture, including the development of a RESTful API and serverless functions, offering a scalable hybrid architechture. I also performed database schema design, integration with third-party services, CI/CD integration and frontend development supervision.

A handful of significant projects I’ve contributed to (completed and in progress) include:

• Main REST API monolith: Developed from scratch a NestJS monolith that serves as the main API for the application. This monolith is responsible for handling business logic and data storage, and it is designed to be scalable and maintainable. I have been involved in the design and implementation of the API endpoints, database schema, integration with third-party services, full CI/CD integration and publishing the API endpoints with a DNS subdomain record and a load balancer.

• Serverless functions: I decided to build serverless architechture for functionalities that I wanted to isolate from the main monolith and allow them to scale independently, using AWS Lambda service.

  • Newsletter subscription: Endpoint that handles subscription of potential new clients (unregistered). This function involved the use of a particular Amazon DynamoDB instance and hCaptcha for human verification. Developed with NodeJS and Javascript.
  • Stripe Event Listener: Function that listens to Stripe events, validates its signature and payload and adds them to a FIFO queue, for batch processing. It is designed to handle unpredictable notification bursts as fast as possible. Developed with Rust.

• Main website: Publicated the website on a custom domain via Cloudflare DNS, and developed full CI/CD integration with Cloudflare Pages, allowing automatic deployment of the website when changes are made to the codebase. I also contributed with some little development tasks.

• Bether app: Developed full CI/CD integration with Cloudflare Pages, including automatic SDK generation for the repository, being aware of the environment (development, production…). I also contributed with SDK fetch calls integration, development of some additional functionalities and transversal refactorings.

• Matrix: IaC repository to handle properly infrastructure management with Terraform CI/CD integration.

I have been working on the development of new features and improvements for the Wattwin web application. My role has involved collaborating with cross-functional teams to design and implement scalable new backend systems, involving backend engineering, libraries development, CI/CD integration tasks and some infrastructure management. My team also brought the use of good development practices, such as unitary, E2E and integration testing.

Some relevant projects I have worked on are:

• Legacy API monolith: Developed new endpoints, refactored existing ones, implemented new features (mixins), fixed bugs and updated outdated dependencies in this repository built with Loopback framework. Relevant technologies used were AWS S3 for generated files storage, AWS SQS for batch processing of heavy tasks and Deepstream client for real-time communication (WebSocket).

• Webhooks microservice: I migrated with my team a legacy Webhooks microservice developed with Express using AWS SQS queues, to a new microservice built with NestJS. This work included performing a deep refactoring, full CI/CD integration, unitary and integration testing, the migration of CRUD endpoints related to Webhooks data from the legacy monolith and the implementation of a dynamic SDK generator in the front-end repo that onboards easily new microservices without disrupting the existing legacy-monolith integration. I performed optimizations on data payloads in internal CRUD operations, reducing the average transaction size by 50%.

• Customer API: Implemented an Infrastructure as Code repository that, through CI/CD integration, managed infrastructure deployment (AWS API Gateway), updating of a Postman workspace documenting the API and the generation of API documentation with a readme.io web page. Due to the environment aware nature of the CI/CD integration, this repository reduced in more than 75% the time required to deploy changes to the API and eliminated 100% of the time required to perform (previously) manual API documentation.

• Backend components: A NodeJS custom package built by our team with almost 100% coverage with unitary testing. I built some library components that are used in the backend monolith and microservices, such as a wrapper of Analytics API SDK library and a Service-Repository pattern implementation of Elasticsearch NodeJS SDK library. Those components are used in the backend monolith and microservices, isolating the responsability of external dependencies upgrade and handling custom business logic inside the library, allowing upgrade external dependencies without breaking changes in the codebase and enforcing DRY development.

• Nest components: Another NodeJS custom library of NestJS components that are used in NestJS microservices, including its unitary and integration testing. Some relevant components I developed are:

  • Modules:
    • ApplicationEventEmitter: Handling of an event emitter that allows the dispatch of events through AWS Simple Notification Service easily using decorators.
    • Elasticsearch: A module that, interconnected with @nestjs/mongoose module, provides full and silent parallelization of data storage in MongoDB and Elasticsearch asynchronously based on MongoDB repository interactions.
    • STS: Use of AWS STS (Security Token Service) to assume roles in AWS accounts dynamically, in order to provide proper roles being aware of application environment (development, production) and developer credentials.
    • Custom config module: Wrapper of ConfigModule that handles the loading of environment variables from AWS Parameter Store, being aware of deployment stage (development, production…) and execution context (local or deployed). The purpose of this module is to provide a single point of configuration for the application, allowing the use of environment variables in a consistent way across all environments and applications, and eliminates the need to persist production credentials on the repositories. It also allows to load non-sensitive credentials from the repository in non-production environments and local context.
    • CrudModule: Integration with @nestjs/mongoose module, providing repositories that might implement repository/schema mixins offered in this module too (workspace based sharding, soft delete through status field…).
  • Guards: Custom guard responsible for request authentication and authorization, forwarding all checks to the existing authentication service.
  • Others: Multiple interceptors, pipes, etc., promoting the use of SOLID principles and DRY development.

• Backend Specialization: Although proficient in full-stack development utilizing Spring Boot (Java) and Angular (TypeScript, HTML, CSS), my primary focus and expertise are in backend development. I have contributed to the creation of robust and scalable server-side solutions, including work on a medical web application used by B Braun GmbH.
• Windows GUI Applications: Developed user-friendly Windows applications using WinDev, with a particular emphasis on backend logic and system integration.
• Database Management: I managed relational databases using Transact-SQL, executing complex queries across multiple SQL servers through OPENQUERY and Linked Servers to optimize data retrieval and storage.
• Statistical Analysis Software: Designed backend systems for statistical analysis software, ensuring efficient data processing and user-friendly interfaces.
• Hardware Troubleshooting: Proficient in resolving hardware issues, including access points, wired links, and power supplies, to ensure seamless industrial system operations.

Completed my final semester internship at ITNow, where I worked on an existing database credentials management microservice. I developed additional features that enabled the integration between multiple new and existing internal microservices, improving system efficiency and interoperability.

Internship evaluated with a 10/10 score.